Cosentino, G;
Jiménez-Serra, I;
Caselli, P;
Henshaw, JD;
Barnes, AT;
Tan, JC;
Viti, S;
... Wu, B; + view all
(2019)
Interstellar Plunging Waves: ALMA Resolves the Physical Structure of Nonstationary MHD Shocks.
The Astrophysical Journal Letters
, 881
(2)
, Article L42. 10.3847/2041-8213/ab38c5.
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Abstract
Magnetohydrodynamic (MHD) shocks are violent events that inject large amounts of energy in the interstellar medium dramatically modifying its physical properties and chemical composition. Indirect evidence for the presence of such shocks has been reported from the especial chemistry detected toward a variety of astrophysical shocked environments. However, the internal physical structure of these shocks remains unresolved since their expected spatial scales are too small to be measured with current instrumentation. Here we report the first detection of a fully spatially resolved, MHD shock toward the infrared dark cloud (IRDC) G034.77-00.55. The shock, probed by silicon monoxide (SiO) and observed with the Atacama Large Millimeter/submillimeter Array (ALMA), is associated with the collision between the dense molecular gas of the cloud and a molecular gas flow pushed toward the IRDC by the nearby supernova remnant (SNR) W44. The interaction is occurring on subparsec spatial scales thanks to the enhanced magnetic field of the SNR, making the dissipation region of the MHD shock large enough to be resolved with ALMA. Our observations suggest that molecular flow–flow collisions can be triggered by stellar feedback, inducing shocked molecular gas densities compatible with those required for massive star formation.
| Type: | Article |
|---|---|
| Title: | Interstellar Plunging Waves: ALMA Resolves the Physical Structure of Nonstationary MHD Shocks |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/2041-8213/ab38c5 |
| Publisher version: | https://doi.org/10.3847/2041-8213/ab38c5 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | ISM: clouds G034.77-00.55; ISM: molecules; ISM: supernova remnants W44; shock waves |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10082426 |
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